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[prj]

Hello,

I have a 2.5TD with AR25 box.
There is an issue with the box once it warms up. Drives perfectly when cold though.
Fluid/filter change has been done three days ago.

It seems as if there is no fourth gear. If I run the box in "3", it operates as it should.
If I run it in "D" after some town driving, then when switching into fourth - be it from third or second, it goes "out of gear".
Basically when going 50kph (35mph), the car does not accelerate unless you rev it to about 3400 rpm. If you floor it at this point, the acceleration makes me think it's stuck in first.
If I rev it past the limiter, it changes into third gear with a strong jerk, and the box goes into limp mode (3rd gear only).

If I manually select "3", it goes into third gear, and can be driven normally.
There is no issue driving in "D" on the highway, overtaking etc.

Getting the software of the box upgraded, but I doubt that will do anything for me.

Does anyone know what the issue could be? 4th gear worn out? Some seals inside the box being weak and once the oil gets thinner with temperature not holding enough pressure to keep it in gear?
I haven't disassembled an autobox (yet). Friend of mine who did it for a living, said there is a disc (or drum, hard to translate) that wears out on these boxes, which enables fourth gear...

[unlucky alf]

You might find its only a lazy solenoid if you are lucky, but of course the AR25 isnt the strongest of boxes thats why TD owners tend to go for an AR35 when replacing or chipping the ECU.

[Jimbob]

does sound like it could be one of the solenoids..

has the fluid change made any difference to the issue?
better or worse?

I presume there were no small bits of plastic in the sump when you did the change?

[unlucky alf]

does sound like it could be one of the solenoids..

has the fluid change made any difference to the issue?
better or worse?

I presume there were no small bits of plastic in the sump when you did the change?

As Jimbob says, perhaps when you had the ATF change the small sump wasnt removed which is where the plastic bits would be I believe.

[hoofing it]

Hello,

I have a 2.5TD with AR25 box.
There is an issue with the box once it warms up. Drives perfectly when cold though.
Fluid/filter change has been done three days ago.

It seems as if there is no fourth gear. If I run the box in "3", it operates as it should.
If I run it in "D" after some town driving, then when switching into fourth - be it from third or second, it goes "out of gear".
Basically when going 50kph (35mph), the car does not accelerate unless you rev it to about 3400 rpm. If you floor it at this point, the acceleration makes me think it's stuck in first.
If I rev it past the limiter, it changes into third gear with a strong jerk, and the box goes into limp mode (3rd gear only).

If I manually select "3", it goes into third gear, and can be driven normally.
There is no issue driving in "D" on the highway, overtaking etc.

Getting the software of the box upgraded, but I doubt that will do anything for me.

Does anyone know what the issue could be? 4th gear worn out? Some seals inside the box being weak and once the oil gets thinner with temperature not holding enough pressure to keep it in gear?
I haven't disassembled an autobox (yet). Friend of mine who did it for a living, said there is a disc (or drum, hard to translate) that wears out on these boxes, which enables fourth gear...

Did you have the engine running when you were refilling the autobox

[prj]

does sound like it could be one of the solenoids..

has the fluid change made any difference to the issue?
better or worse?

I presume there were no small bits of plastic in the sump when you did the change?

As Jimbob says, perhaps when you had the ATF change the small sump wasnt removed which is where the plastic bits would be I believe.

I don't remember seeing any plastic bits.
There was quite a bit of metal on the magnets, but I was told this was normal for a box which has never had the oil changed before...
I don't think the small sump was removed.

Did you have the engine running when you were refilling the autobox

We filled it, then ran the engine, checked the level, then filled it again.

does sound like it could be one of the solenoids..

has the fluid change made any difference to the issue?
better or worse?

Fluid change made shifts smoother, but no change to the issue.
After the oil in the gearbox gets hot, fourth "slips". Or rather, it goes into first instead of fourth it seems.

[hoofing it]

does sound like it could be one of the solenoids..

has the fluid change made any difference to the issue?
better or worse?

I presume there were no small bits of plastic in the sump when you did the change?

As Jimbob says, perhaps when you had the ATF change the small sump wasnt removed which is where the plastic bits would be I believe.

I don't remember seeing any plastic bits.
There was quite a bit of metal on the magnets, but I was told this was normal for a box which has never had the oil changed before...
I don't think the small sump was removed.

Did you have the engine running when you were refilling the autobox

We filled it, then ran the engine, checked the level, then filled it again.

does sound like it could be one of the solenoids..

has the fluid change made any difference to the issue?
better or worse?

Fluid change made shifts smoother, but no change to the issue.
After the oil in the gearbox gets hot, fourth "slips". Or rather, it goes into first instead of fourth it seems.

The engine has to be running whilst you put the oil in.
Just watch you hands on the exhaust

[TheBoy]

Being a TD, I suspected its just knackered

Solenoid faults tend to bring up telltale before the symptom is felt.  Hydro-mechanical issues tend to light the telltale a second or 2 after the symptoms start.

[prj]

Being a TD, I suspected its just knackered

Solenoid faults tend to bring up telltale before the symptom is felt.  Hydro-mechanical issues tend to light the telltale a second or 2 after the symptoms start.

I don't actually get the light lighting up in the dashboard and I also don't have any faults stored in the gearbox ECU, at least none that I could see using a OBD II scanner.

I ordered a Tech 2 china clone from the bay, will check with that.

Got the TCU software updated today - transmission feels much smoother all around, and so far have not been able to replicate the issue.
However, I suspect that it will still be present after lots of stop and go driving.
I will also check the fluid level...

Anyway, I agree, that probably the box is just worn out, so I will try and look for an AR35 box, but since the car is driveable just fine (if the problem occurs, just put it in "3"), I will not have it as top priority right now.
I doubt there is any point in getting the AR25 reconditioned, as 250nm is silly anyway on a 6 pot diesel, it should do 400nm with ease...
Anyway, I still have my UrS6 with 600nm and thankfully a manual box

[TheBoy]

OBDII doesn't really read gearbox properly.

It does sound hydromechanical, so keep eye out for AR35, as I know the TCM firmware update would not solve that sort of issue (but may help mask it slightly)

[prj]

OBDII doesn't really read gearbox properly.

It does sound hydromechanical, so keep eye out for AR35, as I know the TCM firmware update would not solve that sort of issue (but may help mask it slightly)

I fully agree, I did not want to imply that the software update will solve it.
Will see, drove the car a lot today, and had it not crop up, I'll stay on the lookout for an AR35.

[prj]

So it just died.
Now I get the same issue in each gear, even in first when I apply more than just a tiny bit of torque.
The box also jerks around going in and out of gear all the time.

When coming to a stop it also disengages for a moment then re-engages and the engine sound changes...

So I will be getting an AR35, but since I need the torque converter and bellhousing, could it be that my AR25 torque converter is dead?

[prj]

Any ideas?  :-/

[Omegatoy]

only ever known one torque converter die,and that had a crack in it, so leaked the pressure away, and symptoms do tend to point to dead box surprised you havent had any nasty smells though, 35 is definetly the best way to go!! but change the tc with the box on its end so the box cannot seperate by accident!! it has happened doing it on the floor!!

[prj]

Well, I managed to overheat the box in the end, so it spilled some oil out of the breather system onto the exhaust.
The person behind me was probably not happy

I got an AR35 box coming in from the UK in a few days.
I hope the torque converter is okay.

We'll swap the box and then I guess it's time to read the ECU and find IQ, Boost, Smoke limiter, Torque limiter, Boost limiter, etc... and have a shot at tuning the thing.

Does anyone know if the facelift Omega with the X25DT engine has exactly the same ECU as when they came out in 1994? So MSA11?
If so, that'll be a cakewalk.